How can we match a condition among 2 diff. tables?

Hi,Consider the below... table 'employee' with unique 'emp_id', table 'salesorder' with 'emp_id' and unique 'sales_id'
Remember,both tables include some more different fields.Now, i need to get the details of all employees who did receive
NONEof the salesorders. ie.. i wish to select the records of table 'employee' whose 'emp_id' are not there in table
'salesorder'.Ineed to accompolish in a single query!Thankx in advance.Regards,Bhuvaneswar.